#include <bits/stdc++.h>

using uint=unsigned int;
using ll=long long;
using ull=unsigned long long;
using i128=__int128;

const int N=1e6+5;

void Solve(){
    
    return;
}

int main(){
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr); std::cout.tie(nullptr);
    std::string s;
    std::cin>>s;
    int sum=0;
    if(s[0]!='w')sum++;
    if(s[1]!='h')sum++;
    if(s[2]!='i')sum++;
    if(s[3]!='l')sum++;
    if(s[4]!='e')sum++;
    std::cout<<sum<<std::endl;

    return 0;
}